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Week 3: Computer-Controlled Cutting

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*The individual pieces of the parametric kit.

Group Assignment

Please find the complete group assignment here.

Laser Cutter

Before getting down to the group assignment we began with servicing, maintenance and chores. First we vacuumed the laser bed, and the chamber. Then vacuumed the airfilter, and cleaned it with pressurized air. After reinstalling the air filter, we proceeded to cleaning the laser beam directing mirrors. For this we used a special solvant, and cotton swabs.

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This was our first interaction with the lab’s machinery. The rules and operating steps were clear, and with our instructor’s supervision, everything seemed straightforward. However, once we were on our own, things became confusing quite rapidly. Despite the initial struggle, it was a great experience as we got to mess with the machine without breaking anything, and from then on, everything clicked!

What is kerf?

The term kerf is used in both manual sawing and laser cutting to describe the same thing – the width of the gap left behind after a cut is made, either turned into dust, vaporized or burned away by the saw or laser beam.

In fact with lasers, the cut out shape is slightly wider at the top, making it V-shaped, rather than a straight cut.

kerf *Prompt3.1

Plywood

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I first tried cutting a 3mm plywood for measuring the kerf. I used a method which I looked up in older documentations of students from my node. So, I proceeded with creating 10 small rectangles inserted in a larger frame.

To calculate the kerf we proceeded with the following equation:

Kerf = (innerFrame - rectangleSum) / (rectangleNum + 1)

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kerf = [100,3 - 99,3] / 11
kerf = 0,(09)

Cardboard

alt text The same I attempted with 4mm cardboard, same 10 rectangles inside a frame.

Note: cardboard can deform if not stored properly. Parts under more pressure will be squished and become thinner. This can result in nonuniform pieces.

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kerf = [100,47 - 97,92] / 11
kerf = 0,23

One takeaway we made is that with cardboard the laser burns more material than it does with plywood, whereas the soot accumulated on the edges leaves subtle marks.

Vinyl Cutter

The operations for the vinyl cutter were much simpler than the laser cutter. Only one thing was different – changing the blades. One can damage their material in several scenarios:

  • loose securing of materal
  • wrong cutting force and speed
  • dulled out/chipped blade tip
  • edge thickness setting

vinyl cutter *Prompt3.2

To avoid shredding your vinyl, you must set the stroke thickness to Hairline so the blade treats the path as a single cut line. If the thickness is set to some millimeter not corresponding to ‘hairline’ thinkness, then software interprets it as a filled object, effectively destroy the material.

danger sticker

One of the example we completed as a group was a ‘danger; sign. We first designed a simple example including both icons and finer details – text. Then sent the .svg file to the computer connected to the vinyl cutter. After, we picked a red shiny vinyl roll out, cut it into a small sheet and put it under the blade of the vinyl cutter.

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On the vinyl cutter we measured the size of the material to place the file over a corresponding size in the computer [left image below].

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Once the process was done we first used masking tape to transfer the cutout without deforming it, and used a plastic card to attach it with maximal adhesion. We tried attching it onto a metallic surface, my computer, which it did not stick to. So after, we stuck it onto the CNC room’s door.

Individual Assignment

Parametric Construction Kit

For the construction kit, I came up with a design of two mirrored circle segments, subtracted from a quarter circle. Then the polar curve was rotated around the origin.

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I first created a non-parametric draft of the polar curve, and after took the measurements into the spreadsheet. Then I went back to sketch mode, and assigned their parametric values.

Right-click on a cell > Porperties > Display Unit > Alias

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Assembling these was quite fun. But the larger it got, the more difficult it was to keep the edges intact. The thin and fragile ends would get deformed if inserted improperly, especially after 4-5 attempts the cardboard would get creased at its weakest points.

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Vinyl Cutter

I could not come up with something extrordinary to test the applications of the vinyl cutter, so I stuck to making a branded sticker.

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Yet again, I have continued with the series of projects based on my favicon. As I had previously created the .svg of it, I did not need to convert it from the 2D model made in FreeCAD. I simply removed the infill of the logo in Figma, and cut out the outline of it.

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At first I was concerned that the thin tips would be damaged when transfering from the backing tape onto the computer. But again, I used masking tape and all was good when transfering these.

Conclusion

I found quite fascinating working with a laser cutter, especially cutting cardboard. I am sure I will never forget the burnt smell of when opening the chamber door of the cutter.

With the vinyl cutter I am still struggeling to see its full use-potential. Though we have been told that it’s probably one of the most underrated tools in the labs, I believe in it, and still look for ways to harness its best use cases. But so fat, for me it’s a complex sticker cutter [I know that we can cut copper sheets on it too].

Resources

Source files:

Danger Sticker

Prompts

Prompt3.1 It’s known that a kerf in laser cutting is the width of the material that is vaporized or burned away by the laser beam as it makes a cut. I need visuals for it, please make it as simple as you can. So simple so that a 5 year old would understand.

Prompt3.2 Can you create an illustration for a vinyl cutter? Simply its layers, how the vinyl has a backing paper, and how the blade runs over it.